Multilayer structure, device using the same, method for producing the multilayer structure, and method for producing the device

Abstract

Provided are a novel multilayer structure that can be used to protect a device and a device using the multilayer structure. The disclosed multilayer structure is a multilayer structure including a substrate and a barrier layer stacked on the substrate. The 3% strain tension of the substrate in at least one direction is at least 2000 N/m. The barrier layer contains a reaction product (R). The reaction product (R) is a reaction product formed by a reaction at least between a metal oxide (A) and a phosphorus compound (B). In an infrared absorption spectrum of the barrier layer in a range of 800 to 1400 cm −1 , a wavenumber (n 1 ) at which maximum infrared absorption occurs is in a range of 1080 to 1130 cm −1 . A metal atom constituting the metal oxide (A) is essentially an aluminum atom.

The invention claimed is: 
     
       1. A multilayer structure comprising:
 a substrate; 
 a protective layer that is an outermost layer of the multilayer structure; 
 a barrier layer stacked on the substrate between the substrate and the protective layer; 
 wherein: 
 a 3% strain tension of the substrate in at least one direction is at least 2000 N/m, 
 the barrier layer comprises a reaction product (R) formed by a reaction at least between a metal oxide (A) and a phosphorus compound (B), 
 in an infrared absorption spectrum of the barrier layer in a range of 800 to 1400 cm −1 , a wavenumber (n 1 ) at which maximum infrared absorption occurs is in a range of 1080 to 1130 cm −1 , 
 a metal atom of the metal oxide (A) is essentially an aluminum atom, 
 the protective layer consists of a resin or the resin containing an ultraviolet absorber, 
 the resin comprises (1) an ethylene-tetrafluoroethylene copolymer or (2) an acrylic resin, 
 when the resin comprises an acrylic resin (2), the multilayer structure further comprises an adhesive layer disposed on the protective layer between the substrate and the protective layer, and 
 the adhesive layer comprises a polyvinyl acetal. 
 
     
     
       2. The multilayer structure according to  claim 1 , wherein the phosphorus compound (B) has a plurality of sites capable of reacting with the metal oxide (A). 
     
     
       3. The multilayer structure according to  claim 1 , wherein the metal oxide (A) is a hydrolyzed condensate of a compound (L) comprising the metal atom to which a hydrolyzable characteristic group is bonded. 
     
     
       4. The multilayer structure according to  claim 3 , wherein the compound (L) comprises at least one compound (L 1 ) represented by the formula (I):
   AlX 1   m R 1   (3-m)   (I),
 
 wherein: 
 X 1  is selected from the group consisting of F, Cl, Br, I, R 2 O—, R 3 C(═O)O—, (R 4 C(═O)) 2 CH—, and NO 3 ; 
 R 1 , R 2 , R 3 , and R 4  each independently is selected from the group consisting of an alkyl group, an aralkyl group, an aryl group, and an alkenyl group; and 
 m is an integer of 1 to 3; and 
 wherein: 
 when a plurality of X 1  are present in the formula (I), the plurality of X 1  are the same or different from each other; 
 when a plurality of R 1  are present in the formula (I), the plurality of R 1  are the same or different from each other; 
 when a plurality of R 2  are present in the formula (I), the plurality of R 2  are the same as or different from each other; 
 when a plurality of R 3  are present in the formula (I), the plurality of R 3  are the same or different from each other; and 
 when a plurality of R 4  are present in the formula (I), the plurality of R 4  are the same or different from each other. 
 
     
     
       5. The multilayer structure according to  claim 1 , wherein the phosphorus compound (B) is selected from the group consisting of phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, and a derivative thereof. 
     
     
       6. The multilayer structure according to  claim 1 , wherein the barrier layer is stacked on first and second surfaces of the substrate. 
     
     
       7. The multilayer structure according to  claim 1 , wherein the multilayer structure has a vapor transmission rate, under conditions of 40° C. and 90/0% RH, of not more than 0.005 g/(m 2 ·day). 
     
     
       8. A device comprising a protective sheet for protecting a surface of the device, wherein
 the protective sheet is the multilayer structure according to  claim 1 . 
 
     
     
       9. The device according to  claim 8 , wherein the device is a solar cell, a display, or a lighting device. 
     
     
       10. The device according to  claim 8 , wherein the device is a flexible device. 
     
     
       11. A method for producing the multilayer structure according to  claim 1 , the method comprising:
 (i) feeding a substrate from a first roll of the substrate in a feed direction in such a manner that the feed direction coincides with the at least one direction; 
 (ii) forming a precursor layer of a barrier layer on the substrate; and 
 (iii) winding the substrate, which has undergone (ii), on a second roll, 
 wherein (ii) comprises:
 mixing a metal oxide (A), at least one compound having a site capable of reacting with the metal oxide (A), and a solvent, thereby preparing a coating liquid (U) comprising the metal oxide (A), the at least one compound, and the solvent; and 
 applying the coating liquid (U) onto the substrate, thereby forming the precursor layer on the substrate, 
 wherein the at least one compound comprises a phosphorus compound (B), the number of moles of metal atom present in the at least one compound is in a range of 0 to 1 times the number of moles of phosphorus atom present in the phosphorus compound (B), and a metal atom of the metal oxide (A) is essentially an aluminum atom. 
 
 
     
     
       12. The method according to  claim 11 , further comprising treating the precursor layer after (ii) and before (iii), thereby forming the barrier layer on the substrate. 
     
     
       13. A method for producing a flexible device comprising a protective sheet for protecting a surface of the device, the method comprising:
 (a) preparing a protective sheet that is wound on a roll and that comprises a substrate whose 3% strain tension in at least one direction is at least 2000 N/m and a barrier layer is formed on the substrate; and 
 (b) moving a flexible base of the flexible device on which an element is formed, and simultaneously feeding the protective sheet from the roll in a feed direction in such a manner that the feed direction coincides with the at least one direction, thereby stacking the protective sheet on the base to cover the element, 
 wherein the protective sheet is the multilayer structure according to  claim 1 . 
 
     
     
       14. The multilayer structure according to  claim 1 ,
 wherein 
 a coefficient of variation of a vapor transmission rate of the multilayer structure is from 0.085 to 0.523, 
 the coefficient of variation is obtained by dividing a stability of the vapor transmission rate by an average value, mg/(m2·day), of the vapor transmission rate, 
 the average value and the stability of the vapor transmission rate are calculated from measured values of the vapor transmission rates of ten pieces sampled from the multilayer structure, and 
 the stability of the vapor transmission rate means a standard deviation of the measured values. 
 
     
     
       15. A multilayer structure comprising:
 a substrate; 
 a protective layer that is an outermost layer of the multilayer structure; 
 an adhesive layer disposed on the protective layer between the substrate and the protective layer; 
 a barrier layer stacked on the substrate; 
 wherein: 
 a 3% strain tension of the substrate in at least one direction is at least 2000 N/m, 
 the barrier layer comprises a reaction product (R) formed by a reaction at least between a metal oxide (A) and a phosphorus compound (B), 
 in an infrared absorption spectrum of the barrier layer in a range of 800 to 1400 cm −1 , a wavenumber (n 1 ) at which maximum infrared absorption occurs is in a range of 1080 to 1130 cm −1 , 
 a metal atom of the metal oxide (A) is essentially an aluminum atom, 
 the protective layer comprises an acrylic resin, and 
 the adhesive layer comprises polyvinyl acetal. 
 
     
     
       16. The multilayer structure according to  claim 1 , wherein, when the resin comprises the ethylene-tetrafluoroethylene copolymer (1), the multilayer structure further comprises an adhesive layer disposed on the protective layer between the substrate and the protective layer, and
 the adhesive layer comprises a two-component reactive polyurethane adhesive agent.